Telemetry drill pipe with thread electrode



June 30, 1970 M. N. PAPADOPOULOS 3,513,603

TELEMETRY DRILL PIPE WITH THREAD ELECTRODE 2 Sheets-Sheet 1 Filed Oct.28, 1968 FIG. 2A

INVENTOR:

. M.N. PAPADOPOULOS HIS ATTORNEY June 30, 1970 M. N. PAPADOPOULOS3,518,608

TELEMETRY DRILL PIPE WITH THREAD ELECTRODE Filed Oct. 28, 1968 2Sheets-Sheet 2 r f r \5 Q BY: W 7.2-0

HIS ATTORNEY flG 2| INVENTOR M. N. PAPADOPOULOS FIG.

United States Patent O" 3,518,608 TELEMETRY DRILL PIPE WITH THREADELECTRODE Michael N. Papadopoulos, Houston, Tex., assignor to Shell OilCompany, 'New York, N.Y., a corporation of Delaware Filed Oct. 28, 1968,Ser. No. 770,063 Int. Cl. E21b 1/06; H01r 3/04 US. Cl. 339-16 7 ClaimsABSTRACT OF THE DISCLOSURE Drill pipe constructed of a plurality of pipesections attachable to one another in an end-to-end manner by means ofcooperating threaded connector means. Each section has associatedtherewith insulated electrical conductor means running alongsubstantially the full length thereof and connected at each end toelectrode means which comprise a portion of the threaded connectormeans. When the pipe sections are attached together, the electrode meansof adjacent sections are in cooperative engagement, thereby providing anelectrical path along the full length of the drill pipe string.

This invention relates to apparatus for use in drilling oil and gaswells while at the same time being utilized to transmit telemetric datafrom the bore of the hole being drilled. More particularly, the presentinvention relates to a drill pipe construction which incorporateselectrical conductor means and cooperating electrode means to provide anelectrical path along the full length of the drill pipe string.

When drilling a bore hole or otherwise carrying out operations withrespect to a well through the use of a pipe string, it is oftendesirable to send or receive electrical signals between the surface anddownhole. It is a known practice in the art to incorporate transducer orother devices at selected locations downhole, such as on the drill bit,to detect such operating conditions as drilling pressure, temperature,resistivity, and the like, and relay such information to the surface bymeans of electrical signals. In addition, it is often desirable to sendsignals from the surface to a downhole location for various purposes.

Numerous arrangements have been employed in the past for transmittingthese electrical signals between downhole and the surface. One approachhas been to in corporate in each pipe section an individual electricalconductor, such as an insulated wire or conduit, with some means forelectrically connecting the conductors together as the pipe sections arejoined during the course of operations. Such arrangements have beencharacterized by the fact that they are often complex and prone tomechanical failure after repeated usage. In addition, many arrangementsof the prior art type require the use of specially designed drill pipeat great cost and expense to the operator.

SUMMARY OF THE INVENTION It is therefore a primary object of the presentinvention to provide an improved telemetry apparatus of simpleconstruction which incorporates conventional drill pipe and which isexceedingly rugged in construction whereby it may be used repeadlyWithout substantially diminishing the effectiveness thereof.

This and other objects have been attained in the present invention byproviding a drill pipe constructed of a plurality of conventional pipesections attachable to one another in an end-to-end manner by means ofcooperating threaded connector means. Each pipe section is modified byrunning lengthwise therealong electrical conduc- Patented June 30, 1970tor means which is connected at the terminal ends thereof to electrodemeans comprising a portion of the threaded connector means. Theelectrode means comprise thin strips of a conductive metal such ascopper bonded into position by means of a resinous materal havinginsulator characteristics in such a manner that the strips form aportion of the connector threads at both the box and pin ends of thepipe section. In addition, the electrical conductor means itself (whichmay be in the form of a copper wire) is bonded into position along thepipe section by means of the insulating resinous material.

DESCRIPTION OF THE DRAWING Other objects, purposes, and characteristicfeatures of the present invention will be obvious from the accompanyingdrawing and from the following description of the invention. Indescribing the invention in detail, reference will be made to theaccompanying drawing in which the like reference characters designatecorresponding parts throughout several views, and in which:

FIG. 1 is a longitudinal view taken in partial crosssection illustratinga section of telemetry drill pipe with thread electrode means accordingto the present invention;

FIG. 2 is a cross-sectional view taken along a portion of the drill pipeof FIG. 1;

FIG. 2A is a view similar to that shown in FIG. 2 but illustrating analternative embodiment of the present invention;

FIG. 3 is a diagrammatic view illustrating portions of cooperating boxand pin elements of adjacent pipe sections in the respective positionsassumed thereby when the sections are end-connected; and

FIG. 4 is an enlarged cross-sectional View illustrating details of theelectrode means utilized in the present invention.

Referring now to FIG. 1, a drill pipe section incorporating elements ofthe present invention is indicated generally by means of referencenumeral 11. As is clearly shown in that figure, drill pipe section 11has a pin end 12 and a box end 13. The intermediate portion of drillpipe section 11 comprises an elongated tubular element or portion 14with the inner wall thereof defining a throughbore 15 in the usualmanner. As is conventional with respect to drill pipe constructions,internal threads 16 are provided about a portion of the inner peripheralsurface of box end 13 while external threads 17 are provided about aportion of the outer periphery of pin end 12. It is of course to beunderstood that as pipe section 11 is joined in an end-to-end mannerwith other pipe sections (not shown), the internal threads 16 willcooperate with external threads, similar to threads 17, of one adjoining pipe section while external threads 17 will cooperate withinternal threads, similar to threads 16, of the other of said adjoiningpipe sections, thereby maintaining said sections in coupledrelationship. The drill pipe is constructed of steel material except forthose portions thereof which will be described below and constitutemodifications to the above-described conventional drill pipe section inaccordance with the teachings of the present invention.

As may be seen with reference to FIGS. 1 and 2, running lengthwise alongelongated tubular element 14 within throughbore 15 is an electricalconductor means comprising copper wire 21. Wire 21 is maintained in afixed position relative to the inner peripheral wall of cylinder element14 by means of an electrically insulating material 22 such as epoxycement or resin. As may be seen most clearly with respect to FIG. 2, thewire 21 may be imbedded in a pool of epoxy cement or resin formed alongthe inner wall of tubular element 14. In this manner the Wire will beprotected from drilling fluid abrasion and/or from possible impactdamage from wire-line or other tools which may be utilized duringoperations. It is to be understood, of course, that the resultingdecreased internal diameter of the pipe section at its minimum is stilllarger than the undisturbed diameter near the joint, and that it isstill large enough to readily carry out drilling operations withoutsubstantially impeding the flow of drilling fluid in the pipe, andwithout impeding at all the passage of tools.

In an alternative embodiment shown in FIG. 2A a channel 23 may be formedlengthwise in tubular element 14 with the wire 21 being substantiallycentrally maintained in the channel by insulating material 22 which, asstated above, may be epoxy cement or resin, for example. Thisalternative embodiment has the obvious advantage that the fullthroughbore of the pipe section is not diminished upon installation ofthe electrical conductor means. On the other hand, the use of relativelythin-walled drill pipe sections in carrying out the teachings of thisembodiment of the invention may be precluded since a channel formed insuch pipe may substantially weaken it.

Returning once again to FIG. 1, it may be seen that drill pipe section11 is drilled in the vicinity of pin end 12 to provide a throughbore 25into which one end of wire 21 extends. In like manner, a throughbore 26is provided in the vicinity of box end 13 to accommodate the other endof wire 21. It should be noted that the wire is substantially centrallydisposed in the throughbores in an insulated manner by the sameabove-described electrically insulating material 22 utilized to bond thewire to the inner peripheral wall of the elongated tubular element 14.While the paths of throughbores 25 and 26 may be varied in accordancewith the requirements of practice and the exigencies of any givensituation, it is of course desirable that the overall strength of thepipe not be compromised. Accordingly, the various holes drilled andchannels machined should be in regions of considerable pipe thickness.The throughbore paths shown in FIG. 1 therefore are merely by way ofexample and illustrative of paths which may be selected.

Wire 21 is connected at its end to electrode or contact means 31 and 32which are positioned at the pin and box ends, respectively, of the pipesection. It should be noted that one of the contacts (in this instancemale contact 31) actually comprises an integral outer portion ofexternal threads 17 at the pin end of the pipe section. Female contact32, on the other hand is imbedded in the root of box threads 16 to forman integral portion thereof.

Referring now to FIGS. 3 and 4, the construction and placement of thecontacts, as well as their cooperative relationship, will be describedin detail. As stated above, the pipe sections incorporating theteachings of the present invention are adapted to be placed in anend-to-end manner during actual operations. More particularly, theconnector means comprising threads 16 and 17 are adapted to secureadjacent pipe sections together in the well known manner. In addition toperforming this securing function, the threads including contacts 31 and32 cooperate to effect a completed electrical path along the string ofjoined pipe sections. FIG. 3 illustrates this operation in diagrammaticfashion. In this figure, a portion of the pin end 12 of one pipe sectionis shown as being positioned in a portion of the box end 13 of anadjoining cooperating pipe section. The pipe sections during drilling orother operations are maintained in this fixed relative relationship bymeans of threads 16 and 17 in the well known manner. When the pipesections are engaged in this manner contacts 31 and .32 of the adjoiningpipe sections are in communication thereby establishing an electricalpath between the wires 21 of the sections. It is of course to beunderstood that similar couplings are made between adjoining pipesections throughout the entire pipe string.

FIG. 4 provides an enlarged detailed illustration of a preferred form ofcontact to be utilized in accordance with the teachings of the presentinvention. Female contact 32, which is at least one full thread inlength, comprises a relatively thin strip of copper embedded in the rootof the box end threads 16 by means of insulating material 22 and issecured in any known fashion to wire 21 associated with that particularpipe section. A channel is formed in threads '16 on both sides of femalecontact 32 and coextensive with the length thereof so that insulatingmaterial 22 may be accommodated therein to form a zone of insulation 41which flares outwardly from the female contact 32 in the mannerillustrated.

Male contact 31 also comprises a relatively thin strip of copper atleast one full thread in length. In this instance, however, contact 31is bonded as by means of epoxy cement or resin to a thread 17 on pin end12 which has been ground down or otherwise decreased in height in themanner illustrated. Male contact 31 is secured in any known manner tothe wire associated with the particular pipe section and is positionedso that it is flush with the steel male threads associated with theremainder of the pin end. As is clearly shown in FIG. 4 contact 31 issupported in this position by means of insulating material 22 which isfilled in the gap between contact 31 and ground-down thread 17. Itshould be noted that the sides of the thread '17 associated with contact31 are ground down and that some of the insulating material 22 ispositioned in the void created thereby to form a smooth thread surfaceas at 42. When contact 31 is in communication with contact 32 the zoneof insulation 41 surrounds thread surface 42 thereby insuring thatneither contact 31 nor 32 is placed in engagement with the steelportions of pin end 12 and the boxend 13.

The location of contacts 31 and 32 is quite important with respect tothe proper functioning of the apparatus according to the presentinvention. The female copper contact 32 is imbedded in the root of thebox end threads, second thread from the top as viewed in FIG. 1. Themale copper contact 31 is bonded to form a portion of the correspondingthread on the pin end 12. By locating the contacts in this manner theyare located in a region of zero fluid pressure gradient and minimalprincipal stress. This location precludes contact damage throughmisalignment during the makeup of the joint, through accidental pinend-to-box end impact, chain impact, or field-handling of the pipe ingeneral.

Adequate electrical contact is assured by making the female coppercontact face slightly oversize. If, through long use, copper is abradedfrom the copper faces of the contacts in sufficient quantities toprevent engagement therebetween, the problem may be corrected merely bycoating the face of the male contact 31 with a thin film of a mixture ofepoxy cement and copper dust.

Finally, it should be noted that although the root space of some of thebox end threads is effectively plugged with copper and/or insulatingmaterial, the root space of all of the pin end threads is free. Thus,this latter root space maintains the desired communication of fluidbetween the inside of the drill pipe, through the threads, and to theannular space above the threads. As a result, no fluid pressure gradientcan exist across the contacts.

While this invention has been described with particular reference topreferred embodiments thereof, it should be understood that theparticular forms disclosed have been selected to facilitate explanationof the invention rather than to limit the number of forms which is mayassume. Further, it should be understood that various modifications,alterations and adaptations may be applied to the specific formsdescribed to meet the requirements of practice without in any mannerdeparting from the spirit of the invention or the scope of the subjoinedclaims.

I claim as my invention:

1. Apparatus for transmitting electrical signals along a drill stringdisposed in a well borehole, said apparatus comprising:

a plurality of drill pipe sections detachably interconnected in anend-to-end manner, each pipe section including;

an elongated tubular portion having an inner wall defining a throughboreand terminating at the ends thereof with first and second connectormeans, said first connector means comprising a box end and said secondconnector means comprising a pin end, each of said connector means beingprovided with thread means to effect detachable interconnection 'withadjoining pipe sections;

electrical conductor means extending substantially along the length ofsaid pipe section;

electrically insulating material bonding said electrical conductor meansto said pipe sections;

electrical contact means comprising an integral portion of said threadmeans and being fixedly positioned in an insulated manner with respectto the remainder of said thread means by means of an insulating bondingmaterial; and

said electrical conductor means being end-connected to said electricalcontact means to provide an electrical path therebetween which iselectrically insulated from the remainder of said drill pipe section.

2. The apparatus according to claim 1 wherein said electrical contactmeans are in the form of thin strips of copper approximately one fullthread in length and said insulating bonding material is epoxy resin.

3. The apparatus according to claim 2 wherein one of said electricalcontact means comprises a portion of the male threads on said pin endand another of said electrical contact means is disposed in the root ofthe threads on said box end.

4. The apparatus according to claim 3 wherein said electrical contactmeans disposed in the root of the threads on said box end is slightlyoversize to ensure engagement between said contact means and acooperating contact means on an adjoining pipe section.

5. The apparatus according to claim 1 wherein the electricallyinsulating material used to bond the electrical conductor means to saidpipe section is epoxy resin.

6. The apparatus according to claim 5 including a channel formed alongthe length of said tubular portion, said electrical conductor beingcentrally fixedly disposed in said channel by means of said epoxy resin.

7. The apparatus according to claim 3 including a zone of insulationformed by said electrically insulating material adjacent said electricalcontact means disposed in the root of the threads on said box end.

References Cited UNITED STATES PATENTS 959,977 5/ 1910 Washburn et al.2,979,142 4/1961 Reid l105 3,170,137 2/1965 Brandt 339-16 RICHARD E.MOORE, Primary Examiner R. A. HAFER, Assistant Examiner US. Cl. X.R.-104

